Forget going from A to B. Understanding who does what on Britain's railways means getting to grips with a mind-boggling array of acronyms and initials. BBC News Online presents a one stop guide.

So who is who? (in alphabetical order)

ASSOCIATION OF TRAIN OPERATING COMPANIES (ATOC): Unifying body that represents the interests of all 26 train operators. It is responsible for "through-ticketing" (i.e. buying a single ticket which operates for several lines), railcards, and the National Rail Inquiries phone line. Its public face is "National Rail", and it uses the familiar "double arrow" British Rail logo.

DEPARTMENT OF TRANSPORT AND THE REGIONS (DTR): The DTR sets the national strategy and framework for Britain's rail system. The public money which goes to subsidise the rail companies - an amount which should decrease year on year - comes from this department to the SRA which then passes it on. The department also appoints the SRA and the Rail Regulator.

HM RAILWAYS INSPECTORATE: Part of the Health and Safety Executive, the Railways Inspectorate is responsible for ensuring that new track and trains meet safety standards, and for investigating crashes, particularly serious ones.

NETWORK RAIL: The not-for-profit company founded to maintain track and stations after the collapse of Railtrack.

OFFICE OF RAIL REGULATION (ORR): Headed by the government-appointed "industry watchdog" Tom Winsor, the ORR can impose heavy penalties on train operating companies and Railtrack should they fail to reach the required standards. It also sets out the minimum service levels which customers can expect from their train lines.

RAIL PASSENGERS COUNCIL (RPC): The RPC is charged with taking care of passenger concerns. Funded by the government, the RPC is a statutory consumer organisation that monitors and investigates the policies and performances of train and station operators. It has the legal right to make recommendations for changes and investigates passenger complaints that have not been satisfactorily resolved. It was formerly the Central Rail Users Consultative Committee (CRUCC).

STRATEGIC RAIL AUTHORITY (SRA): Responsible for promoting rail use and strategically developing the rail network, the SRA was behind the newly announced Strategic Plan.

The SRA:
 awards franchises to the train companies
 gives loans, grants and guarantees for the development of railways
 filters the government's subsidy for train operating companies
 can ask the rail regulator to require train companies to make specific investments
 draws up blueprints for expanding railways as part of an integrated transport network

The SRA came into existence in February 2001. It was formerly the Shadow Strategic Rail Authority (SSRA) and before that the Office of Passenger Rail Franchising (OPRAF).

TRAIN OPERATING COMPANIES (TOCs): The 26 individual companies which took over the running of lines from British Rail. Examples include Virgin, GNER, Connex, Midland Mainline etc.